1. Field of the Invention
The present invention relates to an image forming apparatus such as a printer and a control method for the image forming apparatus. More particularly, the present invention relates to an image forming apparatus that makes it possible to select a mode relating to issuing a warning or error warning when the toner cartridge is empty and so forth, and to a control method for the image forming apparatus.
2. Description of the Related Art
Conventionally, an image forming apparatus using an electronic photocopying technology forms a color image by means of development units of four colors C (cyan), M (magenta), Y (yellow), and K (black). When this image forming apparatus uses toner of the same colors in large amounts, the time taken for the toner of the color used to run out is short in comparison with the toner of the other colors and it is accordingly necessary to perform a large number of toner exchange operations.
For this reason, a plurality of development units of the same color are provided in an attempt to alleviate the work involved in changing the development units to enable a large amount of development with toner of this color (Japanese Patent Application Laid Open No. 2002-351190, for example). Further, alleviation of the exchange work is achieved by loading developer of the same color in all four development units and using the next development unit when there is very little developer in the first development unit (Japanese Patent Application Laid Open No. 2003-316106, particularly [0063] to [0077], for example).
Meanwhile, conventionally, a color printer with development units of four colors issues a warning when the toner of each color is about to run out and performs processing and so forth to warn of an error when the toner runs out. The printing operation has conventionally been continued following the warning processing.
However, there are also cases of image forming apparatuses in which a plurality of development units holding toner of the same color are mounted where printing is executed continuously even when the toner has run out or when the toner is about to run out. This is because it is possible to perform printing continuously if a development unit in which a certain toner has not run out is used even when another toner has run out.
Moreover, in the case of this image forming apparatus, it is convenient to first warn of an error or warning when all the toner has run out or is about to run out instead of issuing a warning or error also when the toner of one development unit has run out or is about to run out.